Let a contact run through a journey multiple times

Let a contact run through a journey multiple times

Is there already a solution available to let contacts run through a journey multiple times?
I have a demo request form + journey, and it is desirable that contacts can run through multiple times.

Same for a general whitepaper download form with a hidden field for the type of whitepaper. If this can not be solved I will need to create a flow for every single whitepaper.